Constitutive activity of Sauromatum guttatum alternative oxidase in Schizosaccharomyces pombe implicates residues in addition to conserved cysteines in a-keto acid activation

Crichton, Paul G, Affourtit, Charles, Albury, Mary S, Carre, Jane E and Moore, Anthony L (2005) Constitutive activity of Sauromatum guttatum alternative oxidase in Schizosaccharomyces pombe implicates residues in addition to conserved cysteines in a-keto acid activation. FEBS Letters, 579 (2). pp. 331-336. ISSN 0014-5793

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Abstract

Activity of the plant mitochondrial alternative oxidase (AOX) can be regulated by organic acids, notably pyruvate. To date, only two well-conserved cysteine residues have been implicated in this process. We report the functional expression of two AOX isozymes (Sauromatum guttatum Sg-AOX and Arabidopsis thaliana At-AOX1a) in Schizosaccharomyces pombe. Comparison of the response of these two isozymes to pyruvate in isolated yeast mitochondria and disrupted mitochondrial membranes reveals that in contrast to At-AOX1a, Sg-AOX activity is insensitive to pyruvate and appears to be in a constitutively active state. As both of these isozymes conserve the two cysteines, we propose that such contrasting behaviour must be a direct result of differences in their amino acid sequence and have subsequently identified novel candidate residues.

Item Type: Article
Additional Information: All co-authors were postdocs in my lab where the research was carried out. Results demonstrate that constitutive alternative oxidase activity is not due to the presence of cysteines as previously proposed by others but due to upstream residues.
Schools and Departments: School of Life Sciences > Biochemistry
Depositing User: Mary Albury
Date Deposited: 06 Feb 2012 20:33
Last Modified: 22 Mar 2012 12:45
URI: http://sro.sussex.ac.uk/id/eprint/26576
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